Its a very competitive job market and if you go to an employer and say I can only program in assembly and whats more I refuse to use anything else, he will waste no time at all in inviting you for an interview.Its the same as if you were to say I refuse to work with anything but hand drawn logic diagrams.
people whine and say they cannot get a job, well if you are not prepared to jump through hoops there are plenty out there who will.if you cannot program at least a bit in C and you refuse to learn then you only have yourself to blame when employers refuse to look at you.
Its like people who will only use pic processors, pics are for old men who do Morse decoders written in basic for the radio rig in the garden shed.
Also I am afraid that it has to be said very few employers will be impressed by someone who only uses assembler on an ancient 8 bit processor, there may be a lot out there still, but the world has moved on in the past 30 years. These days you can use knowledge of the 8052 registers to show you understand how basic processors work but that's about it.